Grain distributors are used in grain elevators to distribute grain among one of a plurality of receiving ducts that lead to storage bins or silos. In a grain distributor, a housing encloses a distribution spout that is rotated by a drive motor among multiple discharge positions. Each of the discharge positions is located at a receiving duct. In the prior art, a control wheel is connected to the spout and rotates along with the spout to the various selectable discharge positions.
In some grain distributors, the control wheel includes a plurality of code clusters that can be sensed by sensors, for example, inductive sensors. A code cluster is associated with each discharge position. Each of the code clusters has a unique series of data digits and a series of sequencing digits adjacent to the data digits. The data digits and sequencing digits are read as the digits pass by a sensor that includes a first sensor unit and a second sensor unit. The sensor units are operably connected to a control processor for identifying the position of the spout. The control processor allows the data digits to be read only when a sequencing digit is also being read. When a particular discharge position is selected at the control console, the control processor operates the drive motor until the data digits corresponding to the desired discharge position have been sensed by the sensors. The control processor then continues to operate the drive motor for a pre-selected period of time and stops the motor at a point where the discharge spout should be properly positioned at the selected discharge receiving duct.
The coded portion of the control wheel also includes a position proof window or position proof digit for each coded portion. Each of the position proof windows is positioned on the coded portion so as to confront one of the sensors when the discharge spout has been properly positioned at each discharge position. The sensor detects the proof window to confirm that the discharge spout is aligned with the selected receiving duct at the selected discharge position.
The value of grain crops is closely tied to the consistency of the grain delivered. The accidental addition of a different type of grain to a grain crop can cause a dramatic reduction in the value of the crop. For example the inadvertent mixing of soybeans with corn at the grain elevator can lead to a significant financial loss. Accordingly, it is important that the distribution spout be properly aligned with the appropriate receiving duct to avoid the unintentional intermixing of different grain products, which can result in significant losses to the operator of the grain elevator.
Because of the size of grain elevators, it is not uncommon for the control panel for the grain distributor to be located several hundred feet away from the grain distributor itself. The grain distributor typically is positioned near the highest point of the grain elevator, while the control computer or panel is typically located at ground level.
Once a grain distributor is installed, it is necessary to calibrate the sensors and electronics and program the computer so that the grain distributor can be accurately controlled from the computer panel. In the prior art, this is accomplished by stationing a worker in a location where the worker can observe the location of the spout in the grain distributor.
The worker is equipped with a radio and a work light and observes the motion of the grain distributor while it is being controlled by the computer and relays messages to the programmers far below to adjust the position of the distribution spout relative to each receiving duct so that these positions may be programmed in a computer memory for future use. For example, the observer will report to the programmer that the spout is located in proper alignment with a discharge position. More likely, however, the observer will report that the spout is misaligned and needs to be advanced a small distance. The programmer adjusts the position of the spout based on the observer's instructions. If the distance is misjudged and overshot, the observer will instruct the programmer to move the spout backward somewhat. The programmer does so. Once the spout is aligned with a particular discharge position the position is programmed into memory. This process is repeated for each position of the spout until all proper spout positions are properly aligned and placed into memory.
This situation is time consuming and labor intensive because the worker must position themselves so that they can see the grain distributor and communicate with the programmers by radio. The spout of the grain distributor may weigh 1200 to 1500 pounds and when in motion must be approached with caution.
Distribution spouts are sometimes moved by an electric brake motor. An electric brake motor is an electric motor that includes a brake that is applied to the motor shaft or armature when power is no longer applied to the motor in order to secure the brake motor and the distribution spout in position until actuated again. Brake motors are known to be fairly reliable at stopping the spout at a desired location. The brake motor stops the motion of the spout as instantly as possible. While brake motors are fairly reliable, they are sometimes not sufficiently reliable to prevent unintended mixing of types of grain. Coasting of the brake motor and spout when a signal is sent to stop the motion of the spout can vary considerably depending upon temperature and other environmental conditions. In extreme cold, lubricants tend to be thicker and the brake more effective, thus causing quicker stopping of the spout. When temperatures are very warm, lubricants are thinner and the brake is less effective, allowing a larger amount of coasting after some types of motors are inactivated.
Accordingly, the position proof window and the sensing of the position proof window assure that the grain distribution spout is properly positioned to accurately deliver grain to the desired receiving duct.
The large mass involved in moving a 1200 to 1500 pound grain distribution spout, places a good deal of strain on spockets and chains that are used to move the spout, particularly in pendulum style grain distributors. If the spockets or chains fail, the spout drops toward a vertical position and can misdirect the flow of grain. As discussed above, the financial consequences of misdirecting and mixing for example, corn and soy beans can be significant.
The grain distribution spout can be moved from its desired distribution position by a discontinuity of the grain flow. For example, a frozen lump of grain may cause the spout to shift position. In addition, an electrician or other maintenance worker can accidentally move the grain distribution spout and cause a loss of calibration. The grain may then be misdirected into an adjacent discharge position causing an undesirable mixing of grain types and attendant loss of grain purity and value.